1. Field of the Invention
The present invention relates to a vehicular lamp with breathing air holes formed in the rear wall of a lamp body, which cooperates with a front lens to define a lamp chamber.
2. Related Art
A conventional vehicular lamp of this type is typically illustrated in FIG. 7. The illustrated lamp is a vehicular headlamp. As shown, a lamp chamber of the headlamp is defined and hermetically closed by a lamp body 1 and a front lens 2. A reflector with a bulb, which is not shown (as a light source) inserted thereinto is supported by an aiming mechanism A such that it is tiltable back and forth as well as to the right and left. The aiming mechanism A is composed of two aiming screws 3 and 4 and one ball joint 5. An opening 1a for facilitating a bulb exchange is formed in the rear wall of the lamp body 1, and numeral 8 is a bracket used for fixedly mounting the headlamp on a vehicular body.
An air hole 6 is formed in the rear wall of the lamp body 1 as shown in FIGS. 7 and 8. The air hole 6 sets up a communication between the inside and outside of the lamp chamber. In other words, the vehicular lamp or its lamp chamber breathes through the air hole 6 to prevent dew from being formed on the front lens 2.
As illustrated in FIG. 8 in an enlarged view, the air hole 6 is defined by a cylindrical portion 1b protruded outward from the rear wall of the lamp body 1. A flexible tube 7 is fit to the cylindrical portion lb: one opened end of a flexible tube 7 is tightly coupled with the cylindrical portion 1b, while the other opened end is faced downward. Such a coupling of the flexible tube 7 makes it difficult for dust particles and water to enter the lamp chamber S through the air hole 6.
The diameter of the air hole 6 is small. Because of this, the breathing action of the lamp chamber is unsatisfactory. Further, the air passage continuous to the air hole 6 is possibly narrowed in its diameter or even closed, for example, where another member is put on the flexible tube 7. The breathing action, which is unsatisfactory, is thus further deteriorated. In this case, the dew-formation preventing effect is also deteriorated, as a matter of course.
One solution for this problem is to increase the diameter of the air hole 6 (which is circular in cross section) and the inside diameter of the flexible tube 7.
The rear wall of the lamp body 1 is generally curved in shape. Further, various members and components, such as the bulb-exchange opening 1a, the aiming mechanism A and the mounting bracket, are attached to the rear wall of the lamp body. For this reason, it is technically difficult to form the air hole 6 of the sufficiently large diameter at a desired location on the rear wall of the lamp body 1 without interfering with the above members and components.